Biomedical subjects

S Carvalhal

Publications and source records attributed to S Carvalhal.

At least 19 recordsLinked to original sources

PubMed1994

[Mitral valve prolapse and cusp elasticity].

PURPOSE: To verify if systolic bulging of floppy mitral cusps can to elastic behavior of their myxomatous collagen tissue. METHODS: Five hearts with floppy mitral valves obtained from autopsies were distended with air (20 to 250 mmHg) through a catheter connected to the left ventricle. It was observed if some area of the atrial surface of the coapted cusps showed variable bulging according to the variation of air injection pressures. Molding of those surfaces (gypsum) allowed the same kind of analysis by other four researches. It was analyzed the cut surfaces of these radially sectioned molds. Lately, isolated tendinae chords were submitted to repeated tractions and observed if they exhibited elastic behavior. Histological study defined the presence of collagen myxomatous degeneration and quantified the amount of elastic tissue. RESULTS: In no case it was detected elastic bulding of mitral cusps. Cut surfaces of the molds confirmed that no increment of the prominent areas occurred, even in those regions with extensive, histologically confirmed, myxomatous substitution of the native collagen tissue. CONCLUSION: Increment of the degree of mitral bulging occurring during ventricular systole can not be ascertained to cusp elasticity but probably to papilar muscle traction.

Elasticity↗

PubMed1993

[Relationship between volume reduction of the left ventricle and the increase of mitral valve prolapse. An experimental study in dogs].

PURPOSE: To verify whether accentuated reductions of left ventricular volume lead to mitral valve prolapse. METHODS: Seven mongrel dogs were bled through the internal jugular vein, the systolic systemic pressure being kept between 100 and 140 mmHg by means of continuous infusion of dopamine; the inferior vena cava vein, in tree other dogs, was partially obstructed for 4 to 6 seconds; epicardial echocardiography was carried out in all cases. RESULTS: Reductions of volemia were about 50% of the estimated total blood volume. Systolic internal diameter of left ventricle decreased about 25% and systolic ostial diameter, about 12.5%. Three out of seven died suddenly from arrhythmia before one has reached a significant decrease in total blood volume; one showed momentary mitral valve prolapse, during a period of hypotension; however, this prolapse disappeared completely when systemic blood pressure was restored by increasing the dopamine dosage; one dog had slight systolic displacement of the anterior cusp toward left atrium (0.5mm) and the last two showed no change; one out of 3 dogs submitted to partial constriction of inferior vena cava had systolic displacement of anterior cusp of 1mm; in one case there was an equivalent degree of displacement of the anterior cusp toward the left ventricle and in the last one no change was detected. In all dogs there was a change in the dynamics of mitral valve closure: with accentuated reduction of left ventricular volume the posterior cusp became less mobile, the anterior cusp being the principal responsible for the systolic ostial occlusion. CONCLUSION: Accentuated reduction of dog's left ventricular volume does not, necessarily, cause mitral valve prolapse but only slight displacement of the anterior cusp toward the left atrium in some animals or no displacement at all.

Animals↗

PubMed1981